Remove syntax error...

Author: fabienheureux

.github/workflows/ci.yml

@@ -25,7 +25,6 @@ jobs:
            tox-version: "py38"
          - python-version: 3.9
            tox-version: "py39"
-        python-version: ['2.7', '3.6', '3.7', '3.8', '3.9']
 
     steps:
       - uses: actions/checkout@v2